scholarly journals Nuclear Status of Human Sperm Cells by Transmission Electron Microscopy and Image Cytometry: Changes in Nuclear Shape and Chromatin Texture during Spermiogenesis and Epididymal Transit

1993 ◽  
Vol 49 (1) ◽  
pp. 166-175 ◽  
Author(s):  
Jacques Auger ◽  
Jean-Pierre Dadoune
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Image Cytometry ◽  
Human Sperm ◽  
Nuclear Shape ◽  
Sperm Cells ◽  
Transmission Electron ◽  
Chromatin Texture

Selective resorption in nutritive phagocytes of the sea urchin Anthocidaris crassispina

Zygote ◽  
2004 ◽  
Vol 12 (1) ◽  
pp. 71-73 ◽  
Author(s):  
Arkadiy A. Reunov ◽  
Alexander V. Kalachev ◽  
Olga V. Yurchenko ◽  
Doris W.T. Au
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sea Urchin ◽  
Sperm Cells ◽  
Transmission Electron ◽  
Residual Bodies ◽  
Anthocidaris Crassispina

Phagocytic resorption during spermatogenesis was studied in the sea urchin Anthocidaris crassispina. Nutritive phagocytes in gonad absorbed both waste sperm cells and residual bodies discarded from maturing spermatids, and these materials were subsequently compartmented in heterophagosomes. Based on 180 heterophagosomes examined by transmission electron microscopy, over 99% of heterophagosomes contained either residual bodies or sperm cells only. Simultaneous resorption of sperm cells and residual bodies in a heterophagosome was uncommon, with only ∼0.56% occurrence, suggesting that heterophagosomes have a selective resorption ability in nutritive phagocytes.

scholarly journals 258ULTRASTRUCTURAL STUDY OF STALLION SPERM FOLLOWING THAWING, CAPACITATING AND IVF PROCEDURES: EFFECT OF THE PRESENCE OF CUMULUS-ENCLOSED OOCYTES

2004 ◽  
Vol 16 (2) ◽  
pp. 249
Author(s):  
F. Abbate ◽  
P.G. Germanà ◽  
S. Colleoni ◽  
F. Gandolfi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Developmental Competence ◽  
Lower Percentage ◽  
Sperm Cells ◽  
Transmission Electron ◽  
Intact Membrane

The use of IVF in horses has a limited efficiency, reflecting low oocyte developmental competence and inadequate sperm capacitation procedures. In a preliminary study, using carboxyfluorescein diacetate/propidium iodide staining, we determined that the freezing-thawing procedure left only 56.6±3.4 % of the sperm cells with an intact membrane. The following incubation in TALP-IVF induced membrane damage at high rates with only 9.58±1.8 % of them intact after 18h. However, the presence of at least four cumulus-enclosed oocytes (CEO) in the medium significantly increased the number of membrane-intact spermatozoa at the end of incubation (53.87±1.99%). This indicated that the sperm thawing and capacitating procedures can damage the cell membrane but the presence of four or more CEO in TALP-IVF could prevent further damages. The aim of the study was to investigate in detail the membrane damages and to analyze the differences induced by the presence of CEO. Spermatozoa were thawed in water at 37°C, and centrifuged for 30 minutes at 600g in a 45–90% Percoll gradient made with modified Tyrode’s medium. The sperm pellet was washed once in the same medium and diluted to a final concentration of 1×106 spermatozoa/ml TALP supplemented with 0.6% (w/v) BSA fatty acid free and 12μgmL−1 heparin (TALP-IVF). Sperm cells were incubated with 0 or 4 in vitro-matured CEO. Sperm cells were examined after thawing, 0, 2 and 18h from the beginning of incubation in TALP-IVF. Each experiment was replicated at least 3 times. Both scanning and transmission electron microscopy were performed on sperm samples fixed in 2.5% glutaraldehyde in 0.1M phosphate buffer, pH 7.2, using standard procedures. Specimens for scanning electron microscopy were examined under a field emission gun JEOL JSM 6301 microscope. For transmission electron microscopy the samples were examined with a JEOL JEM 100 SX. A minimum of 25 cells were analyzed for each group. Immediately after thawing, damaged spermatozoa showed, on the surface of their heads, small vesicles correlated to a progressive process of vacuolisation and degeneration of membrane integrity. The same lesions were visible at all the successive time points taken into account. Moreover, a loss of the acrosome integrity with acrosomal swelling and a decrease of content homogeneity were observed particularly in the spermatozoa cultured for 18 h without CEO. When CEO were present in the IVF medium lesions were visible in a lower percentage of spermatozoa but the type of lesions did not differ from those observed in their absence. These observations confirmed our previous data and gave more details on the lesions that occur during the IVF procedures in the horse. Supported by MURST COFIN grant n. 2001078849.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

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